Thrust bearing to be used in a contaminated environment

ABSTRACT

A simplified trust bearing to be used in a dry powder contaminated environment such as a pasta maker, with the bearing comprising two plates contacting each other face-to-face and through such face-to-face contact transmitting an axial thrust load.

This is a continuation of application Ser. No. 08/369,629, filed Jan. 6,1995, U.S. Pat. No. 5,731,012 which is a continuation of applicationSer. No. 08/205,498, filed Mar. 4, 1994, now U.S. Pat. No. 5,421,713,which is a continuation-in-part of application Ser. No. 08/059,388,filed May 11, 1993, now U.S. Pat. No. 5,324,185.

BACKGROUND—FIELD OF THE INVENTION

The present inventions are directed to home electric appliances to makepastas, pastries, cookies hors d'oeuvres and other extrudable foodproducts.

BACKGROUND—DESCRIPTION OF PRIOR ART

Automatic home food mixing and extrusion appliances have been in commonuse for many years. Automatic pasta making appliances which both mixdough and automatically extrude dough through a die have been patentedand in use in the U.S. at least since the late 1970s. In general suchappliance have a configuration which includes a bin containing rotatingblades, feeding an extrusion screw which forces the mixed materialsthrough an extrusion die.

For the most part, existing pasta makers are limited in capacity, aremessy and time consuming to use, and have little versatility.

SUMMARY OF INVENTION

The present inventions improve on prior devices in many areas.

Advantages of the present inventions will become apparent from thefollowing description and illustrations of a preferred embodiment.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of an embodiment constructed according tothe present inventions.

FIG. 1A is a detail of FIG. 1 showing the control switch.

FIG. 2 is a top perspective view of mixing and extruding components.

FIG. 3 is a longitudinal vertical section through the center of theembodiment taken along line 3—3 of FIG. 4.

FIG. 3A is a detail of FIG. 3 showing sections of the extruder chamber,extruder screw, die nut, and extrusion die.

FIG. 4 is a front elevation of the embodiment.

FIG. 5 is a cross-sectional view of the mixing bin 22 taken along line5—5 of FIG. 3.

FIG. 6 is a perspective view of a bearing washer 154.

FIG. 7 is a sectional view of the bearing washer shown in FIG. 6 as wellas portions of components surrounding the washer.

FIG. 8 is a sectional view through the extruder taken along line 8—8 ofFIG. 12.

FIG. 9 is a perspective view of a measuring cup.

FIG. 10 is a longitudinal vertical section through the center of themeasuring cup shown FIG. 9 taken along line 10—10 of FIG. 9.

FIG. 11 is a perspective view of the step shaped enclosure subassemblyof the embodiment.

FIG. 12 is a top view of the extruder housing subassembly of theembodiment.

FIG. 13 is a backside view of the extruder housing shown in FIG. 12.

FIG. 14 is a top forward looking perspective view of the embodiment'smixing bin.

FIG. 15 is a front elevation view of the mixing bin.

FIG. 16 is a section of FIG. 12 taken along line 16—16 of FIG. 12.

FIG. 17 is a section of the lid of the embodiment taken along line 17—17in FIG. 18.

FIG. 17A is a detail of the lid shown in FIG. 17 showing how it couplesto the mixing bin and step shaped enclosure.

FIG. 18 is a top view of the lid shown in FIG. 17.

FIG. 19 is a rear elevation of the lid shown in FIG. 17

FIG. 20 is a side elevation of the embodiment's mixing blade.

FIG. 21 is a front elevation of the mixing blade shown in FIG. 20.

FIG. 22 is a schematic of the embodiment's motor control circuit.

FIG. 23 is a block diagram of the circuit shown in FIG. 22.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

A preferred embodiment of the present inventions has a motor 24 rotatedmixer and extruder 30 contained in clear polymeric enclosures 22, 32.The motor 24 and associated transmission 26 are contained in a steppedshaped enclosure 28 (see FIG. 10) which supports and cradles a clearplastic mixing bin 22 within its step. An auger extrusion screw 30 iscontained in a cylindrical extruder housing 32 which protrudes into thefront 33 of the bin 22 and continues out in front 33 of the flat frontface 37 of the bin 22. Whether the embodiment mixes or extrudes iscontrolled by the direction of rotation 34, 36 of the motor 24 andconsequent rotation of the mixing/feeding blades 102, 104, 106, 108, 110and auger extrusion screw 30. Reverse rotation 34 of the blades 102,104, 106, 108, 110 and screw 30 backs dough out of the extruder housing32 and into the mixing bin 22; forward rotation 36 feeds the dough intothe extruder screw 30 which in turn presses dough against and throughthe extrusion die 38. The embodiment may be used as only a slow speedmixer or as both a mixer and extruder. As an example, bread dough mightbe mixed in the unit without reversing the motor to extrude. Instead themixed dough would be removed from the bin 22 and baked in a conventionalmanner.

Specially designed embodiment extrusion dies 38 permit repeatedextrusion without intervening cleaning, in part due to die extrusionholes 168 which are contoured to permit dough which dries hard in theholes between extrusion cycles to be extruded.

Specially designed dies with over 20 degrees of taper in their extrusionholes closest to the extruder screw, also make it easy to clean eitherwet or dry food stuffs and dough from the dies.

A measuring cup 40 with indicia 39 marked on its transparent ortranslucent sides 42 and a guillotine lid 44 simplifies and makes moreprecise dry and liquid measurements. Precision is important in manyextruded farinaceous food recipes and other extruded food products

A pin 228 projecting from the measuring cup's 40 base 41, helps, whenthe cup is shaken, to break up and mix ingredients being measured. As anexample, the pin 228 helps break up and mix the yokes and whites of eggswhen they are being measured. This simplifies mixing and generally makesit quicker. It also eliminates having to clean a fork or other mixinginstrument. In home pasta makers ease of operation and cleanup isimportant to both the marketer and the end user.

The mixing cup's lid 44 conveniently flips down 37 when open 198 to makethe cup 40 easier to handle.

A rotating cutter arm 46 wipes the front face of the extrusion die 38and makes cutting extruded materials a quick and simple process.

This preferred embodiment of the present inventions comprises a twopiece molded polymeric stepped shaped enclosure 28 containing areversible permanent magnet dc motor 24 whose horizontal shaft 48 ispositioned pointing fore 33 to aft 31 within the enclosure 28.

The permanent magnet dc motor provides the high torque and quietoperation desirable in a home food product mixer/extruder.

The motor 24 is powered by wall power conveyed through a cord enteringthe rear 31 of the unit. After entering the enclosure and before flowingto the motor 24, the ac current coming through the cord is controlled ina conventional manner in sequence through: a single-pull-single-throwsafety interlock momentary-on microswitch which is interconnected to themixing bin's lid; a full bridge rectifier; and adouble-pull-double-throw three position forward-off-reverse switch 50,all of which are conventional and only partially shown in the drawings.

As an alternative, a more sophisticated circuit might be utilized incombination with the above mentioned safety and forward-off-reverseswitches. Such a switch/circuit combination might, as an example,provide, in addition to safety interlock, current rectification, currentcontrol and direction reversal, all or some of the following features:

A) automatic resetting electrical overload protection to prevent motordamage when heavy mechanical loads are placed on the motor. As anexample, this might prevent motor damage if extrusion were attemptedbefore pasta flour had been fully mixed with liquid,

B) electric fuse protection for safety against internal electricalmalfunctions,

C) switching delay in reversing motor shaft rotation from forward toreverse or reverse to forward to prevent stress conditions which mightshorten motor life,

D) electrical motor breaking by placing a resistance load between themotor terminals to rapidly slow motor shaft rotation,

E) switching delay to eliminate switch contact arcing when turning theunit on,

F) rectification of input electrical power from alternating current todirect current,

G) alteration of input voltage so, as an example, a 120 volt motor mightoperate from a 230 volt power source,

H) reduction of RF emissions,

I) timing functions so, as an example, the mixing and/or extrusionscycles might be automatically timed,

Of course, such a circuit might provide additional features as well,such as indicator lights, as an example for on/off, or mix, and extrude,or lights indicating improper component assembly, etc.

FIGS. 22 and 23 show a circuit 244 which provides several of the abovefeatures (including features A, B, C, D, F, and H from the above list).

Basically this circuit 244 works as follows.

The circuit 244 shown in FIGS. 23 and 24 will provide protection for aDC motor against overload or sudden direction reversal. This isaccomplished by sensing the motor current and then taking appropriateaction if necessary. The circuit can be divided into the functionalblocks shown in FIG. 23 to help clarify it's operation. The correlationbetween the functional blocks and the schematic is as follows:

Functional Block Schematic Components Power Input and Rectification PlugP1, switch SW1, fuse F1, and diode bridge D1 Circuit Power SupplyResistor R4, diode D9, and capacitor C2 Load Sense Resistor Powerresistor R1 Power Switch Power transistor (MOSFET) Q2, resistors R5,R10, and R11 Snubber Network Power resistor R13, capacitor C3, and diodeD10 On/Off/Reverse Switch DPTT switch 50 DC Motor DC motor 24 OverloadShutdown Resistors R2 and R3, capacitor C1, and SCR Q1 TransientOverload Shutdown Transistors Q3 and Q4, (w/reset) resistors R6, R7, R8,R9 and R12, diodes D4, D5, D6, D7 and D8, zener diodes D2 and D3, andcapacitors C4 and C5

The Power Input and Rectification block shown in this circuit is for usewith 120 VAC, 60 Hz power. It provides a power cord and plug (P1),safety interlock switch (SW1), safety fuse (F1), and a full-wave bridgerectifier (D1) to convert the AC into unfiltered DC. This block can beany other circuit or device that provides power appropriate for thechosen DC motor (24). The design presented for this block is forillustrative purposes only.

The Circuit Power Supply block is a simple, unregulated Diode(D1)/Capacitor (C2) power supply. The resistor R4 is added to limit theinrush current at power up to provide long-term, reliable operation.

The Load Sense Resistor (R1) is used to detect motor current. Since allpower that flows through the DC motor (24) also flows through the FET(Q2) and through this resistor, the voltage across this resistor isproportional to the motor current.

The Power Switch block comprises of the FET Q2 and resistors R5, R10 andR11. The FET is the actual switching device while the resistors providedefault control voltage to the gate terminal of the FET. Note that themaximum recommended gate voltage of a FET is 20V. Zener diode D2 assuresthat the gate voltage in this circuit does not exceed 18V. The SnubberNetwork block uses R13 to dissipate excess motor energy in the event themotor direction switch 50 is suddenly thrown from one direction to theother. Diode D10 is reverse-biased during normal operation an prohibitsR13 from dissipating energy. Capacitor C3 is used to limit dv/dt so thatno damaging high-voltage transients are presented to the drain terminalof the FET.

The On/Off/Reverse Switch (50) is used to control the state (on or off)and the direction (normal or reverse) of the DC Motor (24).

The Overload Shutdown block uses Silicon Control Rectifier (SCR) Q1 toturn off the FET (Q2), and thus the DC motor, if the current drawn bythe DC Motor (24) exceeds a given average value. A resistor dividercomprising of resistors R2 and R3 determine the exact overcurrentthreshold. Since R2 and R3 are placed across the Load Sense Resistor(R1), the voltage at the junction of R2 and R3 is proportional to themotor current. This voltage is fed to the gate terminal of the SCR,which has a rated turn-on threshold voltage. Capacitor C1 is alsoconnected to this junction to provide an averaging effect so that thecircuit doesn't trip on normal power surges such as during motorstart-up.

The Transient Overload Shutdown (w/reset) block uses transistor Q3 toturn off the FET (Q2), and thus the DC motor, if the current drawn bythe DC Motor (24) exceeds a given instantaneous value. This occurs whenthe voltage across the Load Sense Resistor (R1) exceeds approximately2.8V, which is the sum of three forward-biased diode drops (D4, D5 andD6) and the base-to-emitter voltage of transistor Q3. Once Q3 is evenslightly turned-on, it's collector-to-emitter voltage begins to drop andtransistor Q4 looses it's bias current (and immediately shuts off),causing transistor Q3 to turn-on even harder since RS is now free topass current to Q3's base via capacitor C4 and diode D7. As long as Q3is turned-on, the FET (Q2), and thus the DC motor, are turned offbecause the FET's gate terminal is pulled to ground via connection toQ3's collector. This motor-off condition remains until the voltageacross capacitor C4 reaches the clamping voltage of zener diode D3,after which transistor Q3 looses it's base drive current and turns backoff. When Q3 turns off, Q4 regains it's base drive current through R11,R10 and D2. As Q4 turns back on, capacitor C4 quickly discharges throughR7 and D8 to prepare the circuit for another shutdown if necessary.Resistor R6 is added to prevent damaging high-current transients fromflowing through D4, D5, D6, and Q3. Capacitor C5 eliminated falsetriggers due to typical DC motor electrical noise. Resistor R12 keepsthe base voltage of Q3 at ground to prevent false triggering when anovercurrent condition does not exist.

Circuits for adding the other features mentioned above such as timingand indicator lights are well known and thus are not shown here.

On the most forward 33 end of the motor shaft 48 there is a fan 152mounted to, and rotated by, the motor shaft 48. This fan 152 is disposedwithin a cylindrical fan duct 64 which is vented at its front 33 endthrough a right segmented vent 57 in the lower portion of the step ofthe forward piece 67 of the enclosure 28.

Adjoining this first segmented vent 57 on its left 58 in the forward 33most area of the lower part of the step of the forward piece 67 of theenclosure 28, and contiguous with the first segmented vent 57, is asecond segmented vent 66 in communication with and alternating thedirection of the fan 152 driven air flow through the first segmentedvent 57.

The step shaped enclosure 28 is mostly sealed so that during embodimentoperation, air is drawn into 74 and through the second vent 66, over themotor 24 and out 70 through the first vent 57 during ingredient mixing;and, when the motor is reversed, air is drawn into 71 and through thefirst vent 57, over the motor and out 76 through the second vent 66during ingredient extrusion.

During both ingredient mixing and extrusion, air moved by the fan helpscool the circuit described earlier 244 (FIGS. 22 & 23) and the motor 24.The circuit 244 is mounted in the forward 33 lower step 67 of the stepshaped enclosure 28 just behind the left vent 66 with its boardpositioned vertically and pointing fore 33 to aft 31 (FIG. 4). In thispositioned it is in the air flow created by the fan 152 both duringmixing and extrusion.

During ingredient extrusion, air exhausting 76 out the second vent 66blows in a generally horizontal and downward direction helping to drythe ingredients which have been extruded. This is helped becauseexhausted 76 air has been warmed by passing over the motor 24 andcircuit 244.

This reciprocating fan driven air movement is facilitated by thecylindrical fan duct 64 (FIGS. 3 & 4) which surrounds the perimeter ofthe fan blade 152 and connects air entering the fan blade solely anddirectly with the first segmented vent 57 and prevents air exiting thefan blade from reversing direction and reentering the fan blade until ithas been exhausted 76 from the second vent 66 and performed its dryingfunction. Having air movement created by both the first 57 and second 66segmented ducts creates more air turbulence in the drying area just infront of the ducts 57 66 than a single air flow and thus enhancingingredient drying.

Additionally, the air flow during extrusions partially pressurizes theenclosure 28 thus helping to prevent flour or other contaminants fromentering it.

Air from the fan is blown directly onto the motor 24 during extrusionwhen the motor is experiencing heavy mechanical loads and needs cooling.Air is pulled over the motor 24 during mixing when mechanical motorloads are low and cooling is not as critical. The permanent magnet dcmotor 24 is more efficient than universal motors commonly used inkitchen appliances and thus produces less heat and needs less cooling.

The aft plate of the motor frame is securely mounted to the forwardfacing flat wall of a rear facing open-box shaped molded gear housing 78which in turn is rigidly connected to the rear piece of the enclosure 80with four screws thus forming a fully enclosed rigid box. The rear pieceof the enclosure 80 is mounted to the front piece of the enclosure 67with an additional four screws thus forming the stepped shaped enclosure28 which contains the aforementioned fully enclosed rigid gear housingbox.

Within this fully enclosed gear housing box, the aft 31 end of the motorshaft 48 axially mounts a primary drive pinion gear 82 on a slip clutchformed by a ball bearing pressing against a “D” flat on the motor shaftwith a set screw adjusted helical spring pressing against the ball. Iftoo much torque is placed against the primary drive pinion gear 82, asan example if dry ingredients are mistakenly extruded, the ball bearingis forced upward by the flat on the motor shaft until it disengages theflat and allows the motor shaft to rotate within the pinion gear.

This type slip clutch is known in principle and has not been illustratedin detail for simplification of illustration. Such a slip clutch safetyfeature is important in a home food product mixer/extruder wheretremendous structurally loads can damage the device if a simple mistakeis made, such as extruding pasta flour before it is fully mixed withliquid.

Alternatively, the pinion gear 82 might be mounted in conventionalmanner directly to the motor shaft 48.

The primary drive pinion gear 82 meshes with a larger first intermediategear which is rigidly and coaxially connected to another pinion gearwhich meshes with a second intermediate large gear, which in turn isrigidly and coaxially connected to another pinion gear which then mesheswith a large final drive gear 84. The transmission is conventional andhas not been shown in detail for simplification of illustration.

This cascading gear transmission, which is entirely disposed within thefull covered box formed between the open box shaped gear housing 78 andrear piece 80 of the two piece enclosure 28, reduces the motor drivespeed by about 100:1, or from a no-load motor speed of about 6,000 rpmto approximately 60 rpm. The gears in this embodiment are fully enclosedbetween the box shaped gear housing 78 and the rear 80 of the steppedshaped enclosure 28 and thus are kept from flour and other contaminationwhich might shorten gear life.

Axle mountings for the two intermediate gears and the final drive gearare front 33 to back 31 within the full covered box are provided and arehorizontally disposed between, and securely connected to, the insideface of the gear housing 78 and the inside face of the rear piece 80 ofthe two piece enclosure. Two metal plates mounted on each end of theaxles and secured by four screws each to the gear housing and rear pieceof the two piece enclosure respectively, help support the axles for thefirst and second intermediate gears.

The transmission is similar to those well known in the art and,therefore, detailed illustration has been omitted for simplification.

An alternative preferred embodiment transmission mounts an 8 degreehelical pinion primary drive gear on the motor shaft. This gear ismolded of acetyl resin and it meshes with a larger second helical gearmade of nylon. The 8 degrees of helix substantially reduces gear noisein this high speed mesh, and greatly increases the strength of the gearmesh while simultaneously not significantly increasing axial thrust onthe motor shaft which might shorten motor bearing life.

Use of an acetyl gear meshing with a nylon gear increases gear life anddecreases gear noise.

The second gear has a pinion spur gear, gear three, concentricallymolded with it. This gear three, occurring in a slower portion of thetransmission, has no helical gear inclination. This increasestransmission mechanical efficiency, while not significantly increasinggear noise.

Gear three meshes with a larger acetyl gear, gear four, which in turnhas a small diameter 8 degree helical drive gear, gear five,concentrically and integrally molded at its center. Again the nylongear, gear three, meshing with the acetyl gear, gear four, reducing gearnoise and increasing gear life.

Finally gear five meshes with the large diameter nylon final drive gear84, gear six. An 8 degree helix is used on the final drive gear toincrease meshing strength and gear life.

This three mesh transmission using helical gears in its first and lastmesh is felt to significantly increase mechanical efficiency within asmall physical package while simultaneously minimizing gear noise.Specifically, the transmission simplifies the gear reduction task intothree stages. Stage one, the high speed mesh from the motor to the firstintermediate gear, takes high rotational speeds which normally causesignificant gear noise and minimizes the sound through use of helicalgear teeth made of dissimilar materials.

Stage two, the intermediate mesh, maximizes efficiency by using astraight spur gear mesh where gear sound is no longer a major factor dueto reduced rotational speeds and where mechanical loads are still lowthus not requiring gears with extraordinary strength.

Stage three, the final mesh, optimizes load transfer through use ofhelical gears.

Compactness, low noise, long life, and the ability to handle heavymechanical loads are all qualities which are particularly important in ahome food products mixer/extruder.

A horizontally disposed mixer/extruder drive shaft 86 couples to thelarge final drive gear 84 though a hexagonal hole 85 in the gear'scenter collaring a hexagonal portion of the shaft 86, see FIG. 3. Usinga hexagonal drive shaft 86 engaging a hexagonal hole 85 gives adequatetorsional coupling strength while insuring easy assembly by havingengagement possible every 60 degrees of shaft rotation. Along with atapered end to the drive shaft, the shaft may simply be shoved into thehexagonal hole in the final drive gear without resistance and it willsimply rotate the 30 degrees or less needed to insert and couple it.This ease of assembly is particularly important in a home foodmixer/extruder, which of necessity must have many assembled pieces.

The drive shaft projects directly and generally horizontally, forward33, through a hole 88 in the forward piece 67 of the enclosure 28, andinto a transparent molded polymeric mixing bin 22 which is cradled inthe step 29 of the step shaped enclosure 28. This mixing bin 22 isgenerally rectangular in plan view and has: an open top; generally flatright 90 and left 92 and front 94 and back 96 (see FIG. 2) side walls;and a near half cylinder bottom wall 98 which is slightly inclineddownward toward the front 33 of the bin 22 (see FIG. 3). Protruding fromthe front wall 94 of this mixing bin 22, and about ⅓ the diameter of themixing bin's cylindrical bottom wall 98, and protruding about ⅓ themixing bin's length into the front 33 of the mixing bin 22 andapproximately concentric with the drive shaft 86 and cylindrical bottomwall 98 of the mixing bin and raised above the cylindrical bottom wall98 of the mixing bin 22, is a cylindrical extruder housing 32.

Directly forward of the final drive gear 84 and mounted on the driveshaft 86 inside the mixing bin 22 on a cylindrical tubular shaft 100which has a hexagonal center bore collaring and engaging a hexagonalportion of the drive shaft 86, is a set of radially disposed mixing andextruder feeding blades 102 104 106 108 110. A key slot 230 disposedoff-center on one of the drive shaft's six flat hexagonal faces engagesa molded in key rib 232 inside the hexagonal center bore of the mixingblade cylindrical tubular shaft 100 and locates the mixing blade, andwon't allow it to be slid on the shaft backwards, and will allow it tobe mounted to the drive shaft at only one angle relative to theextrusion screw. This eliminates the possibility of a user assemblingthe mixing blade on the drive shaft wrong. It also insures that the feedblades 108, 110, described later, will be automatically correctlyaligned and timed to feed ingredients to the extruder screw 30 when thescrew 30 is in a position most able to accept the ingredients. A homefood products mixer/extruder must rely as little as possible oneducating the end user for proper use and assembly.

The orientation between the mixing/feed blades 102, 104, 106, 108 and110 and the extruder screw 30 is critical to optimizing the extrusionrate because if an edge on the extruder screw is crossing or blockingthe extruder feed hole 158 it will have less tendency to acceptingredients than if a valley between the extruder screw threads isexposed in the feed hole 158.

Starting from the back of the mixing bin and moving forward, there arethree straight relatively flat mixing blades 102, 104, 106 mountedorthogonal to the drive shaft's 86 axis of rotation. These blades 102104 106, when turned by the motor/transmission driven drive shaft 86,rotate the outer tips of their blades in close proximity to thecylindrical bottom wall 98 of the mixing bin 22. Each mixing blade 102,104, 106 is generally flat in cross section and angled from the driveshaft's 86 axis of rotation so as to propel ingredients in the mixingbin 22 forward 33, like a propeller, to the front of the mixing binduring ingredient extrusion. This propulsion of ingredients to the frontof the mixing bin during extrusion is also aided by the position of eachmixing blade. When the drive shaft 86 is rotating in extrusion direction36, the rear mixing blade 102 strikes the ingredients first, followed bythe middle mixing blade 104, and finally by the front mixing blade 106.This propels the ingredients from the rear mixing blade 102 to themiddle mixing blade 104 to the front mixing blade 106 and thus from theback 31 of the mixing bin to its front 33.

Viewed from the side, the blades 102, 104, 106 each have a narrow, highaspect ratio, generally trapezoidal outline.

The first mixing blade 102 is positioned in close proximity to the flatrear wall 96 of the mixing bin. The next 104 is positioned about ½ thelength of the cylindrical tubular shaft 100 forward of the first 102 andat 90 degrees counterclockwise rotation 34 from it when viewed from thefront 33 of the drive shaft, and the third 106 is positioned at theforward 33 end the tubular shaft 100, just aft 31 of the back of thecylindrical extruder housing 32, and at 90 degrees counterclockwiserotation 34 from the second mixing blade 104.

These sequenced 90 degree mixing blade placements, as mentioned above,help move ingredients in the mixing bin 22 to the front 33 part of themixing bin during ingredient extrusion. The configuration is also easilymolded, as an example in plastic, without complicated molds.

Forward of these three mixing blades 102 104 106 and mounted integrallyon the same tubular shaft 100, are a clearer blade 108 and an upperextruder feed blade 110. The upper extruder feed blade 110 is supportedby an arm 112 which is also positioned near the front of the tubularshaft and at 90 degrees counterclockwise 34 rotation from the thirdmixing blade 106. This arm 112 is radially disposed and inclined forward33 about 30 degrees off vertical toward the front 33 of the mixing bin.This inclined arm 112 projects the upper extruder feed blade 110 overthe cylindrical rear portion of the extruder housing 32 which protrudesback 31 into the forward 33 portion of the mixing bin 22 coaxial withthe drive shaft 86 and its collaring tubular shaft 100.

The upper extruder feed blade 110 is a narrow flat paddle inclined 5degrees inward off radial disposition to facilitate the correct timingof dropping of mixed ingredients into the extruder feed hole 158. Thisblade's 110 outer edge, when rotated by the drive shaft 86, comes inclose proximity to the cylindrical lower mixing bin wall 98 and itsinner edge rotates at a distance substantially away from the rearprojecting cylindrical extruder housing 32. The forward facing 33 tip ofthe upper extruder feed blade 110 is disposed in close proximity to thegenerally flat forward inside wall 94 of the mixing bin.

The clearer blade 108 is a straight rod-like projection which is mountedparallel with the drive shaft's 86 axis of rotation on another 30 degreeoff vertical forward 33 inclined radial arm 114 which is integral andpositioned on the cylindrical tubular shaft 100 180 degrees opposite thearm 112 holding the upper extruder feed blade 110.

The clearer blade 108 rotates parallel to and in close proximity to thecylindrical outer wall of the extruder housing 32 and at a distancesubstantially away from the mixing bin's lower cylindrical wall 98. Theforward 33 facing tip of the lower extruder feed blade 108 is alsodisposed in close proximity to the generally flat forward inside wall 94of the mixing bin.

During extrusion the leading edge of the clearer blade 108 is parallelto the drive shaft's axis of rotation and is inclined like a road graderblade away from the extruder housing 32 to lift ingredients away fromthe cylindrical outer wall of the extruder housing 32 and away from theupper extruder feed hole 158 which the wall 32 contains so as to keepthe feed hole 158 free of ingredients which might bridge the hole 158over and interfere with the extruder's feed.

Disposed on the inside of the mixing bin's 22 generally smooth interiorcylindrically shaped lower wall 98 are a series of discrete, separated,narrow, shallow, sharp, upward facing step shaped protrusions 116 whichon their lower sides incline and blend into the mixing bin's 22 interiorwall 98 thus forming projections with acute triangular vertical crosssections; and rectangular perimeter outlines when viewed in plan. Thesestep shaped protrusions 116 help break up and mix the ingredients in themixing bin when the mixing blades are rotated during either mixing orextrusion.

These protrusions 116 are felt to be novel. By having a plurality ofsteps, as opposed to say a single long step or no step at all as shownin previous art, two advantages are gained. First, ingredients, andparticularly ingredients which become lumped together, are broken up asmall step at a time, thus requiring less power than a system trying tobreak up ingredients over say a single long step or using the geometryof a smooth sided mixing bin.

Second, these small protrusions 116 reduce motor surging. Motor surgingis where a motor suddenly slows down due to additional load, as anexample caused when ingredients being pushed by the mixing blades hit asingle long step or hit smooth sides on a mixing bin. Surging generallyoscillates fast/slow/fast/slow . . . as the ingredients collide with asingle step or mixing bin wall and then become free again. This surgingstrains all mechanical elements within the appliance and shortens motorand mechanical element life. The small protrusions 116 gradually breakup ingredients literally a step at a time and thus significantly reducemotor surging and the damage it may cause.

Surging is also reduced by the disposition of the mixing and feed blades102, 104, 106, 108, 110 on the cylindrical tubular shaft 100. All tallblades 102, 104, 106, 110, those blades that come into close proximitywith the sides of the mixing bin, that includes all mixing and feedblades 102 104 106 110 except the clearer extruder feed blade 108, aredisposed at least 90 degrees to one another. This helps preventingredients bridging between two tall blades as is the tendency of manyingredients. When such bridging occurs, it can also cause motor surgingas clumped bridged ingredients collide with and become free of mixingbin side walls and any contours they might contain. Again, thisreduction of surging might significantly increase the life of motor andmechanical transmission components.

The upper portion the mixing bin 22 is rectangular in horizontal crosssection, with flat vertical walls 90, 92, 94, 96 capped by a detachable,hinged, molded, clear polymeric lid 118. This lid, across its topsurface, is unequally bisected into left 120 and right 122 indentedareas, along a line parallel with the drive shaft's 86 axis of rotation.

The larger right-hand 60 indented area 122 is surrounded by low verticalwalls and has an interior inclined planar surface 124 sloping about 15degrees off horizontal down to the right 60 with this planar surfacepenetrated for about half its width at its right-hand side by an opensegmented grate 126. This inclined planar surface 124 and open segmentedgrate 126 allow flour or other solid ingredients, and/or viscous, orliquid ingredients to be poured, dumped or fed into the mixing bin 22without opening the mixing bin lid 118 and without stopping the machinewhile also preventing fingers or hands from entering the mixing bin.

This segmented grate 126 is felt to be unique. Prior art in motoroperated home appliances in this category do not show openings whichallow the user to introduce solid ingredients, such as flour, into amixing bin without opening the mixing bin lid.

This ability to add, as an example, flour to the mixing bin withoutopening the mixing bin lid is a major advantage. For instance, whenmixing a pasta, a user frequently has to add more flour or liquid tobring the ingredients in the mixing bin to the proper consistency. Beingable to add flour through the lid without stopping the mixing or openingthe lid saves much time and allows a more precise method for obtainingthe proper mix.

The smaller left-hand 58 indented area 120 has a “U” shaped trough 121penetrated at its central base by a narrow slot 128 running fore 33 toaft 31 for most of the trough's length. The trough 121 and slot 128allow liquid ingredients and somewhat viscous ingredients, such as eggsand oil, to be poured into the mixing bin through the mixing bin lid.The trough 121 and narrow slot 128 slow and distribute the entry of theliquid ingredients into the mixing bin.

Across most of the rear of the lid projects a rigid flat lever 130 whichterminates along the full length of its back edge in an upward facinghook 132 which engages a reciprocal downward facing catch 134 in the topof the step shaped enclosure 67, 28 when the lid is closed on to themixing bin 22—see FIG. 17A. This hook engagement securely couples thelid 118 and attached mixing bin 22 to the step shaped enclosure 28 whenthe lid is closed on the mixing bin as shown in FIGS. 3 and 17A. Thehook engagement releases the mixing bin 22 from the step shapedenclosure 28 when the lid is opened as shown in the dotted lines 306 inFIG. 17A. Two small cams 127 on the bottom of the rigid flat lever 130pull the lid to the back 31 of the mixing bin 22 when the lid isclosing, making the lid engage correctly onto the mixing bin.

This is felt to be an advantage over other designs both because itallows the embodiment to be easily disassembled by simply opening thelid and then pulling off the mixing bin from the step shaped enclosure,and because it allows the bin 22 to be resecured to the stepped shapedenclosure 28 by simply closing the lid. It, in combination with the flatrib 148 on the lower front 33 of the mixing bin 22, also allows themixing bin to be loaded either on a counter top or on the step shapedenclosure.

When opened 306 (dotted lines FIG. 17A), the lid 118 may rest in avertical position on top of the step shaped enclosure as shown by thedotted lines in FIG. 17A. This allows easy access to the interior of themixing bin without removing the lid from the stepped shaped enclosure28. From this vertical position 306, the lid 118 may be easily liftedupward and detached clear of the enclosure 28 and mixing bin 22.

Thus this lid 118 design allows:

locking the embodiment's mixing bin 22 to its step shaped enclosure base28 by simply closing the lid 118;

unlocking the mixing bin 22 from its step shaped enclosure base 28 byjust opening the lid and sliding the mixing bin away from the base;

full access to the mixing bin's interior without removing the lid fromthe enclosure 28 and simply leaving it in a vertical position 306;

full removal of the lid by just opening it and lifting it free;

introduction of dry ingredients into the mixing bin 22 without openingthe lid (by using the grate 126);

introduction of liquid ingredients into the mixing bin 22 withoutopening the lid (by using the slot 128).

Also projecting off the rear 31 of the lid 118, and positioned on bothsides of the rigid flat lever 130, are two short vertical ribs 123 and125. Both ribs project back 31 through holes 127 and 129 in the backflat wall 96 of the mixing bin 22, see FIGS. 14 and 17A, when the lid118 is closed on the mixing bin, thus helping to hold the lid onto themixing bin. These ribs couple to the mixing bin near the outer topcorners of the mixing bin and provide, along with the front top cornermounted latches 133 described below, a closed box lid/mixing bincombination which is structurally resistant to the torque produced bythe extruder 30. This rib 123 125 latch 133 combination is felt to beunique in that earlier appliances required heavy metal substructures toresist torquing forces. The right-hand 60 rib 123 is longer than theleft 125, and when the lid is closed on the mixing bin, the right-handrib 123 pivots through a hole 131 in the stepped enclosure, see FIGS. 11and 17A, and contacts the safety interlock momentary-on microswitch (notshown), thus turning the motor off when the lid is opened and preventinga user from inadvertently being hurt by rotating mixer blades.

The front 33 of the lid has a molded on latch 133 comprised of a widehorizontal flexible flat rib 135 connecting the main front portion ofthe lid 118 to the middle of a wide vertical rigid flat rib 137 whichhas left 58 and right 60 rear facing projections 138 on the verticalrib's 137 outer lower front left 58 and right 60 edges which go over andin front of and engage forward 33 facing undercuts 140 disposed on theupper outer front edges of the mixing bin's 22 generally flat outerfront wall 94 when the lid 118 is closed on the mixing bin 22 thuslatching the lid 118 to the mixing bin 22. This latch 133 is opened bymoving the top edge of the wide vertical flat rib 137 backwards 31 withfinger pressure which in turn rocks in teeter-totter fashion the latchprojections 138 on the fulcrum of the flexible flat rib 135 out ofengagement with the mixing bin's upper front edge undercuts 140. Thenatural resilience of the polymeric flexible flat rib acts as a springto reengage this latch when the lid is closed on the mixing bin. Apolymeric material such as polycarbonate is suitable to bias theflexible flat rib 135 so this latch reliably engages.

Polycarbonate is also able to take high temperatures such as are foundin kitchen dishwashers, and it provides high structural strength, so itis suitable for not only the lid (transparent, dishwasher safe,structural and spring latch), but also for the mixing bin (transparent,dishwasher safe and structural) and extruder housing (transparent,dishwasher safe and highly structural) as well.

In the center and bottom of the latch's 133 vertical rib 137 is a tab240 which, when the lid 118 is lowered, engages into a groove 242 on thelarge vertical circular disc 162 which holds the extruder housing 32 andwhich comprise a large portion of the forward 33 wall of the mixing bin22 (see FIG. 4). This engagement between the tab 240 and groove 242,coupled with the bayonet latches 164 on the disc 162 and mixing bin 22,locks the disc 162 to the mixing bin 22 when the lid 118 is lowered.

A tremendous amount of torsional force is carried by the mixing bin 22in the embodiment between where it engages the step shaped enclosure(through pins 143 and 141 and projection 146) and where it engages theextruder housing 32 (through bayonet latches 164). This torsional forceis generated by torsional force at the back of the drive shaft beingopposed by extruder screw resistance in the extruder housing duringextrusion. As mentioned earlier, by being disposed at the upper outercorners of the mixing bin, the above described latches 133 rigidize themixing bin when the lid is closed so the mixing bin acts as a stressedskin closed box, a structure particularly well suited to taking theunusual tortional loads of this particular home appliance embodiment.This lid/mixing bin engagement is different from other similarappliances which rely on less reliable center latches which allowcomparably far more undesirable flexing in the mixing bin 22 than thestructure just described.

The mixing bin 22 on both the upper left and upper right sides of itsflat rear wall 96 has two rear facing cylindrical pins 141 and 143 whichengage holes 145 and 147 in the stepped shaped enclosure 28.Additionally the enclosure has a forward 33 facing shallow cylindricalprojection 146 surrounding the drive shaft 86 entry 85 into the mixingbin 22. This shallow projection 146 engages a hole 149 penetrating theflat rear wall 96 of the mixing bin (FIGS. 11 & 14). For further rigidengagement between the mixing bin and the stepped shaped enclosure,there is a vertical rib 148 projecting from the lower front section ofthe mixing bin. This rib 148 is pierced by two holes 151 and 153 whichengage pins 144 molded into the stepped shaped enclosure 28. Thiscombination of holes 145 147 149 151 153 and pins (projections) 141 143144 146 rigidly secure the torque resistant closed box mixing binstructure to the torque resistant double closed box structure of thestepped shaped enclosure 28 encasing the gear housing 78. This is againa departure from earlier designs for, as an example, pasta makers, whichdidn't use the essential elements of the mixing bin and motor and gearenclosures as major structural elements. This in turn meant earlierdesigns were larger and heavier which is very undesirable in a kitchenappliance which must be moved and stored.

The front 33 of the drive shaft 86 has a helical auger extruder screw 30integrally coaxially molded. This screw 30 is disposed within theinterior 308 of the generally cylindrical molded polymeric extruderhousing 32. The extruder housing 32 in turn projects partially back 31into the mixing bin, coaxial with the drive shaft 86, and partiallyforward 33 out in front 33 of the mixing bin 22.

The rear 31 of the extruder housing 32 which is disposed within the bin22 is capped at its back with an integral vertical wall 150 having acentral hole 302 through which the drive shaft 86 passes. In order toform a thrust bearing surface, where the rear of the extruder screwcontacts this rear vertical extruded housing wall, there is a stainlesssteel washer 152 insert molded to the extruder housing's rear verticalwall 150 and a plastic bearing washer 154 snapped on the back of theextruder screw 30 (FIGS. 3 & 7).

This plastic bearing washer 154 has densely packed bulls-eye-likeconcentric grooves 156 in its rear 31 flat surface which contact themetal washer 152. These grooves 156 provide clearance for dry contentswhich might leak into the bearing area and get trapped between the twobearing surfaces 152 154. The grooves 156 are felt to be novel andsubstantially reduce both bearing wear and bearing noise in the dirty,dusty environment found within the mixing bin 22.

The stainless steel washer 152 both is frictionally compatible with theplastic bearing washing to provide a suitable bearing surface (as anexample between acetyl for the plastic washer and the stainless steelfor the metal washer), and helps to conduct away and dissipate heatwhich might otherwise build up in the bearing. Stainless steel isresistant to corrosion and expands relatively little when heated bybearing forces, thus making it further suitable.

The portion of the cylindrical extruder housing 32 which is disposedwithin the mixing bin 22 is penetrated by an upper extruder feed hole158 and a lower extruder housing clearing hole 160. The larger upperextruder feed hole 158 is generally rectangular in plan view andpenetrates the upper cylindrical wall of the extruder housing 32symmetrically through about 90 degrees of wall arc. The extruder feedhole 158 is open for most of the length the extruder housing 32 iswithin the mixing bin. During extrusion, ingredients to be extruded maydrop to the interior of the extruder housing 32 through this upperextruder feed hole 158.

The smaller lower extruder housing clearing hole 160 is also rectangularand is open through about 30 degrees of extruder housing wall arc in thelower most section of the extruder housing 32. The lower clearing hole160 runs only about ⅓ of the length the extruder housing is within themixing bin, with the clearing hole's 160 back 31 edge directly below theback 31 edge of the helical extruder screw 30 and forward 33 of thebearing 154 on the back of the extruder screw 30 (see FIG. 3).

During mixing, the extruder screw 30 moves materials to the rear 31 ofthe extruder housing 32 where they are cleared out of the extruderhousing mostly through the lower clearing hole 160. This helps preventthe collection of dry flour in the extruder housing during mixing.Contrary to what logically might be expected, the lower cleaning hole160 does not substantially reduce efficiency of the extruder feedmechanism because ingredients falling next to the extruder screw areforced forward by the screw's 30 threads.

It is felt that this hole 160 is both novel and effective in making asimple extruder system.

The extruder housing 32 is integrally molded into a large vertical flatcircular disc 162 which rotationally mounts 36 and dismounts 34 to thegenerally flat mixing bin front wall 94 through three symmetricallyspace bayonet type latches 164 on its perimeter which cooperate withgrooves 165 and stops 167 on wall 94. Within these grooves 165 areprojections 236 which engage detents 238 on the bayonet latches to allowthe latches to engage and couple in only one rotational orientation (oneposition in 360 degrees of arc).

The flat disc 162 and the extruder housing 32 it supports form much ofthe front 33 interior wall of the mixing bin.

On the inside wall of this disc 162 facing into the mixing bin 22, thereis molded a rod-like clearing projection 166 pointing directly back 31toward the rear of the embodiment (see FIGS. 2, 3, 12 and 13). Theleft-hand 58 leading edge 34 of this cleaning projection 166 comprises avertical wall disposed almost over, and a moderate distance from, theright-hand 60 edge of the extruder feed hole 158.

The projection's 166 position is such that when the drive shaft 86 isrotated 34, 36, the lower edge of the upper extruder feed blade 110passes above and in close proximity to the upper edge of the clearingprojection 166, while the upper edge of the clearer blade 108 passesbelow and in close proximity to the lower edge of the clearingprojection 166. During such rotation the rear 31 facing tip of theclearing projection 166 comes in close proximity, but does not touch,the arms 112 114 holding the upper extruder feed blade 110 and clearerblade 108. The projection 166 reduces the amount of ingredients that maycollect on the clearer 108 or upper 110 feed blades by scraping theirupper and lower edges respectively. The scraped dough either then dropsinto the extruder hole 158 or back into the mixing bin.

This arrangement of a clearer blade 108 and an upper 110 feed bladeorbiting inside and outside respectively a cleaning projection 166 isfelt to be novel. Earlier designs have used a large single paddle tolift ingredients into an extruder feed chamber entrance. Such largesingle paddles tend to build up ingredients on their faces and thusbecome clogged and ineffective. By contrast, the small paddle surface onthe upper feed blade 110 has far less tendency to build up ingredientson its paddle surface. The cleaning projection 166 tends to clear excessingredients from the upper feed blade as well. The clearer blade 108provides the benefit of clearing any ingredients which might bridge overextruder feed hole 158 or collect on the cleaning projection 166. Thisis a major advantage as ingredients frequently tend to bridge over feedholes and block the feed of the extruder.

During both mixing and extrusion, ingredients in the bin 22 are mixed bythe mixing and extruder feed blades 20 rotationally 34, 36 passingthrough the ingredients and by the ingredients being pressed andshredded by the mixing and extruder feed blades 20 against the mixingbin's side walls and stepped shaped protrusions 116 thereon.

During extrusion, ingredients in the mixing bin 22 are moved toward thefront 33 of the mixing bin 22 by both the propeller-like mounting angleof the flat mixing blades 102, 104, 106 to the tubular shaft 100 and bythe mixing blades order of progression along the cylindrical tubularshaft 100.

At the front end 33 of the mixing bin 22 the ingredients are lifted bythe upper extruder feed blade 110 from the mixing bin 22 to above theextruder feed hole 158. Most ingredients here naturally drop off theupper extruder feed blade 110 either into the extruder feed hole 158 orback into the mixing bin. Yet other ingredients may stick to theextruder feed blade 110.

As the upper extruder feed blade 110 continues around 36, it passesparallel to and in close proximity to the rod-like clearing projection166. As it passes, excess ingredients are scraped off the extruder feedblade 110 by the rod-like clearing projection 166 and then these scrapedingredients may fall into the extruder feed hole, or fall back into themixing bin, or they stick to the rod-like clearing projection. As theextruder feed blade continues yet further, it passes the bottom of themixing bin 98 where it scrapes off ingredients stuck to it and picks upmore ingredients and repeats the cycle. The step shaped protrusions 116on the cylindrical bottom wall 98 of the mixing bin help in this bytearing and mixing the dough or ingredients passing on the upperextruder feed blade.

Ingredients which get stuck to the rod-like projection 166, as well asingredients which become bridged over the extruder feed hole 158, may becleared by rotation 34, 36 of the clearer blade 108. As the clearerblade 108 rotates 36 it passes just above the extruder feed hole 158 andjust below the rod-like projection 166 and tends to clear them both anddrop ingredients back into the mixing bin 22 or into the extruder feedhole 158.

This method of dough delivery works as a general rule at all levels towhich the bin 22 may be filled. However, when the embodiment isprocessing a full load of dough, because the bin may be full above thedrive shaft 86, for about the first half of the extrusion of the load,the extruder feeding blades 20 may rotate a large mass of dough aroundthe extruder housing and its feed hole 158 and fill the extruder housing32 completely with dough, even to the extent where dough falling intothe feed hole 158 is pushed back out of the hole 158 by extruder screw30 rotation 36. As the load empties, progressively less dough may be fedinto the extruder feed hole 158 particularly as the bin becomes nearempty and the upper feed blade 110 must reach to the bottom of the bin22 and lift the dough through almost 180 degrees of arc to dump it intothe hole 158.

During ingredient mixing, ingredients may also enter the extruder feedhole 158. These ingredients may be cleared from inside the extruderhousing by a combination of the rotation of the extruder screw 30 movingingredients to the back 31 of the extruder housing 32, and the extruderclearing hole 160 allowing the ingredients to drop back into the mixingbin 22.

During ingredient extrusion, ingredients enter the extruder feed hole158 and are propelled toward the front 33 of the extruder housing 32 bythe rotating extruder screw 30 where they are then compressed againstthe extrusion die 38, worked to a malleable consistency, and pressuredthrough the die's 38 openings 168. Four long shallow troughs 170 (seeFIG. 8) in the front 33 half of the interior wall of the extruderhousing 32, and running parallel with the mixer/extruder drive shaft's86 axis of rotation, help the extruder screw 30 build ingredientpressure against the extruder die 38. These troughs 170 are radiallydisposed on the sides facing clockwise 36 extruder screw 30 rotation andare ramped at 45 degrees to radial on the side facing counterclockwise34 extruder screw 30 rotation. This helps prevent pressure on theextruder screw during mixing due to dry flour pressing against the step.Its ramped troughs also provide an additional measure of safety againsta finger being pinched if someone should accidentally leave off theextrusion die and put their finger into the extruder screw duringmixing.

The cylindrical interior of the rear 31 half of the extruder housing issmaller in diameter than the forward half and smooth with no steps. Thisalso helps reduce pressure on the extruder screw during mixing. Also,the thread on the rear of the extruder screw does not extend all the wayto the back of the extruder housing but instead dead ends at the thrustbearing washer 154. This is yet another way of reducing pressure on theextruder screw during mixing.

Capping the front of the extruder housing 32 is a threaded die nut 172capturing a circular disk extrusion die 38. A plurality of femalebuttress threads 174 (FIGS. 3 & 3A) on the inside of the die nut 172hold the die nut in engagement with male buttress threads on the outsideof the front of the extruder housing. Castellated indents 176 on theforward perimeter of the die nut provide engagement for a wrench if thedie nut becomes stuck or is tightened too tight onto the extruderhousing. Motor reversal may also be used to lower pressure on the dienut and make it easier to remove. Motor reversal may also be used toreduce pressure against a die and allow it to be changed for one ofanother shape during extrusion.

An inward projecting lip on the front face of the die nut 172 engagesand captures the outer perimeter of each circular extrusion die.

Two cylindrical tubes 178 180 are integrally coupled parallel with thedrive shaft 86 axis on the right 60 side of the die nut 172. An “L”shaped molded cutter blade 46 easily snap fits into and out of androtates 34 36 in either of the holes in the center of each of thecylindrical tubes 178 180. This blade 46 has an elongated flat surfacewhich parallels the front surfaces of the extrusion dies 38 when thecutters and dies are both mounted to the embodiment. This blade 46 hassharp edges on both sides, and has a small finger handle 182 whichpermits the blade to be rotated 34 36 by hand across the front 33 faceof each extrusion die 38 contacting and scraping the die's front surfaceacross the blade's length thus cutting material extruding through thedie holes 168. One of the tubes 180 is longer and disposed above andparallel to the other tube 178 and permits use of the cutter 46 withdeeper (thicker) dies such as those used to make macaroni. This cutterblade 46 is free to rotate a full 360 degrees which makes it easy tocycle from cut to cut.

Each extrusion die 38 is penetrated front to back by one or more holes168 shaped to produce various cross sections of extruded material. As anexample, a spaghetti extrusion die might have 30-⅛ inch diameter holesspaced on about ¼ inch centers.

Extrusion dies 38 may have holes 168 with cross sections comprising aforward 33 segment having parallel or outwardly divergent walls 184 forat least 0.010 of an inch and a widely taper rear segment 186 with wallsangling at least 20 degrees off the hole's center axis (see FIGS. 3 &3A). This construction differs from conventional die configurations andpromotes both easy cleaning due to the high rear hole taper, andintermittent extrusions without intervening cleanups because materialdrying in the front of the die may be easily extruded through the diedue to the parallel or outwardly divergent wall construction in theforward 33 die hole segment.

The dies are subjected to tremendous pressure during extrusion.Interlocking annular projections on the forward 33 outer perimeter ofeach die 188 (FIG. 3A) and on the rear inner perimeter of the die nutcenter hole 190 engage each other to lock the die in place duringextrusion. This differs from past die constructions which have no suchinterlocking.

During extrusion pressure on the die 38 from material to be extrudedpressing against the die 38 may make the die nut 172 difficult tounscrew. The cutter tubes and their support help give leverage tounscrew the die nut. In addition, a wrench is provided with theembodiment to facilitate removal of the die nut 172. Also, theembodiment may reverse its motor rotation direction to the mix mode andthus lower the pressure on the die nut by reversing the direction ofrotation 34 of the extruder screw. This reversing action makes removalof the die nut much easier.

To measure powder, liquid and other materials being placed in the mixingbin, a measuring cup 40 is provided. This cup is rectangular in planview with transparent generally vertical side walls 42 which are marked39 with horizontal lines and wording for measurement of ingredients, anda guillotine lid 44 which slides horizontally in from the side to bothautomatically and accurately level measured materials and to makepossible dumping materials into the mixing bin either through thesegmented grate 126 in the right-hand side of the lid 118 or directlyinto the uncovered mixing bin 22. The cup 40 has a low wall 200 abovethe lid 44 which prevents the excess flour or other measured materialsfrom dumping off the cup when the lid is closed.

One method to dump materials measured in the measuring cup 40 directlyinto the mixing bin 22 with the mixing bin lid closed (see FIG. 19) is,the materials are first poured into the measuring cup 40 and themeasuring cup's lid 44 is slid 196 to its closed position and the excessmaterials are poured back into their storage container. The closedmeasuring cup is then inverted and placed onto the right 60 side 122 ofthe mixing bin lid 118 with the handle on the measuring cup lid pointingto the left 58 or uphill side of the mixing bin lid. The lid of themeasuring cup is then slid open 198 and the measuring cup shaken left 58and right 60, and/or fore 33 to aft 31 to help sift the materialsthrough the holes in the grate 126 on the right side of the mixing binlid. This shaking action is possible because the inclined planar surface124 on the mixing bin lid's right 60 side is larger than the perimeterof the top of the measuring cup and thus allows room for the cup 40 tobe shaken both right 60 to left 58 and fore 33 to aft 31. Somematerials, such as sugar or durum flour may not require this shakingaction.

The measuring cup 40 also has pouring spouts 202 formed in two forwardupper corners by the thinned side walls. These prevent dripping and helpin easily pouring liquid into the machine either with the lid open orclosed. The measuring cup's lid 40 has stops 220 which prevents the lidfrom being accidentally removed from the cup but allows the cup to befully opened with the lid still mounted to the cup. The lid 44 may bedisengaged from the cup 40 by a firm pull 198 in combination with slightflexing of the lid 44.

The double-pull-double-throw three position forward-off-reverse switch50 has a safety push button 204. The switch is comprised of a threeposition, center off slide switch with a flexing molded rib 204 integralto the rear piece 80 of the two piece enclosure 28 and disposedorthogonal to the wall from which it projects and directly beside theswitch's slide lever 206 (FIGS. 1 & 1A).

The flexing portion 208 of the rib 204 is simply a place where thematerial forming the rib is thinned. It is located at the rib's baseparallel with the wall from which the rib projects and allows the topportion of the rib to flex away 210 from the switch slide while thebottom of the rib closest to the wall from which the rib projectsremains next to the switch slide. The flexing molded rib has a taperedcatch 212 close to its top which is positioned to prevent the switchfrom being moved from its off position to its extrude position withoutthe rib being deflected 210 by finger pressure to one side away from theswitch slide 206. This tapered catch 212, however, because of itsposition and taper in direction of the switch slide travel, does notinterfere with the switch being moved from its off 214 to its mix 216position or vise versa or from its extrude 218 to its off 214 position.

This stop at the off position of the double-pull-double-throw threeposition forward-off-reverse switch 50 helps prolong the lives of themotor 24, switch 50 and other electrical and mechanical embodimentcomponents. This is especially true because the three position switch 50is switching large amounts of dc current which puts very high stresseson switching components, and because the permanent magnet dc motor 24needs to be very large to supply the torque needed, as an example, toextrude pastas, and thus encounters very high mechanical and electricalstresses particularly, as an example, when it is switched too quicklyfrom forward to reverse rotation or when it is extruding thin pastas.Such mechanical and electrical stresses are not common in kitchenappliances and thus the finger activated intermediate stop meansprovides a feature not commonly needed in kitchen venues.

Another alternative to this three position switch is an electroniccontrol circuit which may switch the unit to mix and then to extrude andthen off at either preset or user set intervals. Such electronic controlsystems are today used in such appliances as bread and dough makers.

In operation this preferred embodiment is easy to use. As an example, tomake spaghetti the following could occur. Flour would be poured into themeasuring cup 40 until the cup was slightly over full. The cup wouldthen be tapped on the counter top to lightly pack it. Flour over themeasured amount would be removed from the cup by sliding 196 the cup'sflat lid 44 closed, thus closing the cup and leaving excess flour on topof the cup's lid surrounded by the low walls 200 projecting above thelid 44 of the measuring cup. The excess flour would then be poured backinto its storage container by inverting the cup over the container withthe cup's lid 44 still closed 196.

The flour remaining in the cup would then be dumped into the bin eitherby opening both the cup's and the bin's lids and pouring the cup'scontents into the bin, or by inverting the cup onto the right side 122of the closed bin lid 118 with the cup's lid 44 handle pointing left 58,opening the cup by sliding 198 its flat lid 44 sideways, and repeatedlysliding the cup across the lid left to right and/or fore to aft over thesegmented grate 126 in the right side of the lid. This repeated movementsifts the flour through the segmented grate into the mixing bin.

Generally, before liquid is added to the mixing bin, the embodiment'smotor is turned on to the mix direction by closing the mixing bin lid118 and sliding the double-pull-double-throw three positionforward-off-reverse switch 50 up to the mix position 216. Water, eggsand possibly other liquid ingredients such as vegetable juices or spicesare then poured into the measuring cup to the desired measuring heightmarked on the side walls of the cup. The contents of the measuring cupare then poured into the mixing bin either through the segmented gratein the right-hand side of the mixing bin lid 122 or through the slot 128in the trough on the left-hand side of the mixing bin lid.

After 30 seconds to 5 minutes the ingredients in the mixing bin may befully mixed. This is generally faster than most pasta makers because ofthe mixing blade configuration and because of the shallow steps 116 onthe interior of the bottom wall of the mixing bin which help tear andmix the ingredients.

During mixing and extrusion it may be necessary to add either dry orliquid ingredients to the mixing bin to make a correct mixture. Thesegmented grate 126 on the right-hand side of the mixing bin lid 118 andthe slot 128 in the trough on the left-hand side of the mixing bin lidallow such ingredients to be added without opening the mixing bin lidand thus without interrupting the mixing. Alternatively, the lid 118 maybe opened to add ingredients.

The transparent mixing bin and mixing bin lid are very important inallowing the user to view the ingredients being mixed to determine thatthe mixture is correct, or what is needed to make it correct.

After the ingredients are mixed, the three position forward-off-reverseswitch 50 is then switched down to its extrude position 218 by pressingdown on the switch lever with a finger and simultaneously with the samefinger or another finger pressing against the adjacent flexing rib 204to release the safety catch 212 and allow the switch lever to move intothe extrude position 218.

The catch 212 thus prevents the switch from moving unchecked into theextrude 218 position. It thus aids in delaying the switch in its offposition 214 to allow the motor to slow before being reversed. This inturn helps prolong motor and other component life.

During extrusion, ingredients are further mixed and moved to the frontof the mixing bin by a combination of the propeller-like mixing blade102 104 106 mounting angles and their placement along the tubular shaft100, and by the downward sloping cylindrical lower wall 98 of the mixingbin 22 (FIG. 3). The ingredients are then lifted and dropped into theextruder feed hole 158 in the top of the rear half of the extruderhousing 32 by the upper extruder feed blade 110 and clearer blade 114,and moved and pressured through the extrusion die 38 by the augerextrusion screw 30.

After the ingredient mix passes through the die 38 it can be cut byrepeatedly rotating the cutter blade 46 in front of the die 38. Afterall the ingredients are extruded and the mixing bin is near empty, theembodiment is turned off by pushing three position forward-off-reverseswitch 50 up to its off position 214.

In some cases it may be advantageous to tip the embodiment forward so itrests on its forward two support feet 222 and the lower forward lip 224of the front piece 67 of the two piece step shaped enclosure 28 (FIGS. 3& 4). The embodiment is balanced on the table or counter top 226 to beat stable rest in this forward tipped position and it, through itsdesign form, provides a solid support base in this tipped position (FIG.3).

This forward tip position also allows the embodiment to extrude pastasand other foods which don't extrude easily through a vertical extrusiondie plate. These pastas include corkscrew-like rotini and fuscili aswell as thick forms such as cookies and thick pie crusts among others.This forward tip position may also help in fully clearing the contentsfrom the mixing bin by moving bin contents, and particularly wet orsticky contents, to the front of the mixing bin where they can be pickedup by the extruder feed blades. The embodiment may also be tipped tothis forward position with its die disposed over the edge of a counteror table to help in either extruding or clearing the mixing bin.

Additional pasta can be made without intervening cleanup by adding moreflour and liquid to the mixing bin either immediately or up to one ortwo hours later, and repeating the above process. This repeated mixingis possible because pasta dough which may dry in the front of the dieholes may be easily extruded through the forward portion of the dieholes which have either no taper or an outward tapered. Effectively thisgive this embodiment unlimited capacity, a major competitive advantage.

Also, the slot 128 in the left-hand side of the mixing bin lid and thesegmented grate 126 in the right-hand side of the mixing bin lid allowsingredients to be added to the mixing bin without even opening its lidor turning off the embodiment.

Cleaning the mixing bin and extruder is done by disassembling theembodiment. To do this the lid 118 is opened and then lifted out ofengagement with the mixing bin by rotating the lid to its verticalposition where it is out of engagement with step shaped enclosure andlifting it straight up away from the enclosure. The mixing bin is thenpulled forward and uncoupled from the stepped enclosure by pulling onthe rib 148 near the bottom from the mixing bin and simultaneouslypushing on the pins 144 that pass through the rib.

The extruder housing 32 and integral disc 162 are then disengaged fromthe mixing bin by rotating it counterclockwise 34, thus uncoupling itsbayonet latches 164, and pulling the housing away from the mixing bin.The mixing blades 20 are then slid backward off the drive shaft 86.After the die nut 172 is unscrewed 34 and the die 38 is pulled off, theextruder screw 30 and integral drive shaft 86 is pulled forward out ofthe extruder housing 32. This renders all cleanable parts disassembledand ready for cleaning. Other orders of disassemble are also possibleand would be obvious to a user even after short experience with theembodiment.

Reassembling the unit is done by reversing the above process.

Many foods can be made with the embodiment described including: allkinds of pastas such as rotini, macaroni and spaghetti; cookies such aspeanut butter and gingerbread cookies; pastries such as pie crusts;baked goods such as brownies, bagels and biscuits; and hors d'oeuvressuch as chicken or beef meat balls and cheese dips. Most of these aremade with recipes well known in the art with slight modification toaccommodate rotary mixing and subsequent extrusion.

The structure of the embodiment is unique. A high degree of stiffness isrequired to insure integrity under heavy loads caused by mixing andextrusion. To achieve this, the embodiment comprises two enclosed boxsections. The first is formed by the two halves 66 80 of the steppedshaped enclosure 28 joining. The second enclosed box section is formedbetween the rear piece 80 of the stepped shaped enclosure and the openbox shaped gear housing 78. Both these formations are stress skinstructures which give excellent stiffness and structure to theembodiment.

Flour, liquid and other contaminants can clog gears and shortencomponent life. The embodiment has its gears disposed within a sealedcompartment formed between the rear piece of the stepped shapedenclosure 80 and the open box shaped gear housing 78. This eliminatescontaminate exposure to the gears. The motor 24 and switches areenclosed within the stepped shaped enclosure 28. Openings into this areaare limited to vertical surfaces to minimize contaminate entry.

The embodiment may be made at any convenient scale. As an example, themixing bin may be approximately 6 inches wide, 6 inches deep and 6inches high. The stepped shaped enclosure may be of any size to fit anappropriate motor and transmission.

Also the embodiment may be made of any of a variety of materials suchas: polycarbonate for the extruder housing, lid and mixing bin; ABS forthe stepped shaped enclosure, gear housing and die nut; and acetyl resinfor the dies, extruder screw and mixing blades.

Various changes and modifications to the preferred embodiments will beapparent to those skilled in the art. Such changes and modifications mayinclude, but are not limited to: using more or fewer mixing blades orchanging their shape or layout; reversing the fan air flow; eliminatingthe trough on the left-hand side of the mixing bin lid; having themeasuring cup lid rotatably slide into place; having more or fewer thantwo blades to feed the extruder; changing the shape of the mixing bin ortwo piece enclosure, or measuring cup; using a different transmissionsuch as a belt or worm gear drive; integrating the mixing/extruderblades with the extruder screw; locating the motor in a differentposition such as with its shaft disposed right to left instead of foreto aft; channeling the air flow different such as taking air from belowthe embodiment and blowing at the ingredients emerging from theextrusion die from an enclosure extended to one or both sides of thedie; etc.

Such changes and modifications can be made without departing from thespirit and scope of the invention. Accordingly it is intended that allsuch changes and modifications be covered by the appended claims andequivalents. Upper extruder feed blade 110 is supported by an arm 112lower extruder feed blade 108 is a straight rod-like projection which ismounted parallel with the drive shaft 86 on another 30 degree offvertical forward 33 inclined radial arm 114 which is integral andpositioned on the cylindrical tubular shaft a series of discrete,separated, narrow, shallow, sharp, upward facing step shaped protrusions116 projections 117 and 119 on the interior and exterior of extruderhousing 32 assist in mixing and extrusion detachable, hinged, molded,clear polymeric lid 118 smaller left-hand 58 indented area 120 has a “U”shaped trough 121 right 122 indented areas projecting off the rear ofthe lid, and positioned on both sides of the rigid flat lever 130, aretwo short vertical ribs 123 and 125 larger right-hand indented area 122is surrounded by low vertical walls and has an interior inclined planarsurface 124 sloping about 15 degrees off horizontal open segmented grate126 ribs project back through holes 127 and 129 in the back flat wall 96narrow slot 128 when the lid is closed on the mixing bin, the right-handrib pivots through a hole 131 in the stepped enclosure a rigid flatlever 130 which terminates along the full length of its back edge in anupward facing hook 132 front 33 of the lid has a molded on latch 133upward facing hook 132 which engages a reciprocal downward facing catch134 in the top of the step shaped enclosure 28 wide horizontal flexibleflat rib 135 wide vertical rigid flat rib 137 rigid flat rib 137 whichhas left 58 and right 60 rear facing projections 138 forward 33 facingundercuts 140 flat rear wall has two rear facing cylindrical pins 141and 143 rib 148 is pierced by two holes 151 and 153 which engage pins144 molded into the stepped shaped enclosure 28 two rear facingcylindrical pins 141 and 143 which engage holes 145 and 147 in thestepped shaped enclosure 28 the enclosure has a forward facing shallowcylindrical projection 146 surrounding the drive shaft 86 entry 85 intothe mixing bin mixing bin on both the upper left and upper right sidesof its flat rear wall has two rear facing cylindrical pins 141 and 143which engage holes 145 and 147 in the stepped shaped enclosure 28 thereis a vertical rib 148 projecting from the lower front section of themixing bin shallow projection 146 engages a hole 149 penetrating theflat rear wall of the mixing bin extruder housing 32 which is disposedwithin the bin 22 is capped at its back with an integral vertical wall150 rib 148 is pierced by two holes 151 and 153 which engage pins 144molded into the stepped shaped enclosure 28 stainless steel washer 152insert molded plastic bearing washer 154 snapped on the back of theextruder screw 30 plastic bearing washer 154 has densely packedbulls-eye-like concentric grooves 156 extruder feed hole 158 a lowerextruder housing clearing hole 160 extruder housing 32 is integrallymolded into a large vertical flat circular disc 162 three symmetricallyspace bayonet type latches 164 three symmetrically space bayonet typelatches 164 on its perimeter which cooperate with grooves 165 and stops167 on wall 94 a rod like clearing projection 166 die extrusion holes168 Four long shallow steps 170 in the front 33 half of the interiorwall of the extruder housing 32, and running parallel with themixer/extruder drive shaft 86, help the extruder screw 30 buildingredient pressure against the extruder die 38 threaded die nut 172plurality of female buttress threads 174 Castellated indents 176 on theforward perimeter of the die nut cylindrical tube 178 is integrallycoupled parallel with the drive shaft 86 axis on the right 60 side ofthe die nut 172 One of the tubes 180 is longer a small finger handle 182which permits the blade to be rotated 34 36 extrusion dies 38 may haveholes 168 with cross sections comprising a forward 33 segment havingparallel walls 184 a widely taper rear segment 186 The dies aresubjected to tremendous pressure during extrusion. Interlocking annularprojections on the forward outer perimeter of each die 188 Interlockingannular projections on the forward outer perimeter of each die 188 andon the rear inner perimeter of the die nut center hole 190 engage eachother to lock the die in place during extrusion cup is rectangular inplan view with transparent generally vertical side walls 42 which aremarked 194 with horizontal lines the measuring cup's lid 40 is slid 196to its closed position lid of the measuring cup is then slid open 198cup has a low wall 200 above the lid measuring cup 40 also has pouringspouts 202 double-pull-double-throw three position forward-off-reverseswitch 50 has a safety push button 204 switch's slide lever 206 flexingportion 208 of the rib 204 allows the top portion of the rib to flexaway 210 from the switch slide flexing molded rib has a tapered catch212 switch being moved from its off 214 to its mix 216 position or viseversa or from its extrude 218 to its off 214 position measuring cup'slid had a stop 220 which prevents the lid from being accidentallyremoved from the cup forward two support feet 222 and the lower forwardlip 224 counter top 226 tab 240 which, when the lid 118 is lowered,engages into a groove 242 integral vertical wall 150 having a centralhole 302 the interior 308 of the generally cylindrical molded polymericextruder housing 32 lid is opened as shown in the dotted lines 306 inFIG. 17A circuit 244.

We claim:
 1. A thrust bearing device in combination with a pasta maker or other dry powder contaminated environment comprising: a cavity for receipt of dry powder materials; a rotating shaft carrying an axial thrust load extending into said cavity; a first plate coupled to and rotating with said rotating shaft and said first plate receiving said axial thrust load, and said first plate exposed to dry powder materials in said cavity; and a second plate in said cavity which does not rotate with said rotating shaft having a face contacting a face of said first plate, said second plate also exposed to dry powder materials in said cavity, whereby said thrust bearing device may support said axial thrust load while being exposed to dry powder materials through face-to-face contact between said plates; and wherein either the first plate or the second plate includes a concentric depression.
 2. The thrust bearing device of claim 1 further including at least said first plate or said second plate having depressions in its face configured to receive dry powder material.
 3. The thrust bearing device of claim 2 wherein said depressions are concentric and plural.
 4. The trust bearing device of claim 1 wherein the plate that includes the concentric depression includes a plurality of concentric depressions.
 5. The thrust bearing device of claim 1 wherein both the first plate and the second plate include a concentric depression.
 6. The thrust bearing device of claim 1 wherein both the first plate and the second plate include a plurality of concentric depression. 